DE2625919A1 - PROCESS FOR HYDROALKYLATION OF PARFFIN - Google Patents

Description

UEXKÜLL & STOLBERG PATENTANWÄLTE

2 HAMBURG 52

BESELERSTRASSE 4

DR. J.-D. FRHR. by UEXKÜLL

DR. ULRICH GRAF STOLBERG DIPL.-ING. JÜRGEN SUCHANTKE

Exxon Research and (Prio: June 12, 1975

Engineering Company _{Ü £ J 58g 1? 6} _ ₁₃₁₅₅₎

P.O. Box 55

Linden _f NJ / V.St.A. Hamburg, June 9, 1976

Process for the hydroalkylation of paraffins

The invention relates to a process for the selective catalytic hydroalkylation of paraffinic hydrocarbons with paraffins and / or olefins.

The acid-catalyzed addition of an alkane to another alkane or an alkene is generally known; an alkyl cation which is formed from an isoparaffin with a tertiary hydrogen is usually added to an olefin in the catalytic alkylation of paraffins. This process is used in the petroleum industry to produce highly branched C ₆ -Cg paraffins, which are high quality fuels for internal combustion engines and other machines. The required process conditions and the product composition depend on the particular hydrocarbons used.

Hydrocarbon conversion processes involving metal halides based catalysts are used

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has been described many times. For example, tantalum pentafluoride or niobium pentafluoride in combination with hydrogen fluoride for refining hydrocarbon oils or promoting disproportionation of alkyl-substituted ones aromatic materials are used. In addition, hydrogen fluoride / tantalum pentafluoride and hydrogen fluoride / Niobium pentafluoride good catalysts for isomerization, alkylation and cracking as well as other aromatic reactions.

It has now been found that iso-paraffinic C.- to C ₁ "-hydrocarbons are selectively alkylated with paraffins and / or olefins under alkylation conditions when working in the presence of hydrogen and a catalyst which has one or several Lewis acids of the formula MX, where M is an element of group IIIA, IVB, V or VIB, X is a halogen, preferably fluorine and η is the ratio of halogen atoms to atoms M, which varies from 1 to 8, and as the second component (b) contains a hydrogen halide. The reaction temperatures can generally vary within a wide range, for example from about -1OO ° to +100 ⁰ C, more preferably from about -30 ° C to +75 C., and preferably from about -10 to about +60 It has surprisingly been found that when using a hydrogen halide, preferably hydrogen fluoride together with hydrogen and a metal halide, preferably tantalum

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pentafluoride, niobium pentafluoride, or mixtures thereof, desirable alkylate products can be formed with high selectivity. The process according to the invention thus results in _{an improved selectivity with regard to branched Cg-C 1} “-alkylate products compared to known processes. Preferably, the alkylation process of the invention is carried out in the substantial absence of aromatic compounds. The group designations used are based on the periodic table printed on page 790 in "The Encyclopedia of Chemistry", Reinhold Publishing Corporation, 2nd edition (1966).

One or more components are part of the catalyst system Lewis acids, preferably metal halides. Suitable metal halides include the fluorides, bromides and Chlorides of titanium, vanadium, zircon, niobium, tantalum, chromium, molybdenum, tungsten, arsenic, antimony, bismuth and the chlorides and bromides of gallium and aluminum. Preferred are fluorides of metals of Group IVB and VIB and especially of group V is used. Specific examples of such suitable metal fluorides are antimony pentafluoride, tantalum pentafluoride, Niobium pentafluoride, vanadium pentafluoride, tungsten hexafluoride, Titanium tetrafluoride, molybdenum hexafluoride, bismuth pentafluoride, Arsenic pentafluoride, mixtures thereof and similar connections. The fluorides, chlorides and bromides of phosphorus, especially phosphorus pentafluoride, are also

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if suitable Lewis acids. The metal halides most suitable as a catalyst component are tantalum and niobium halides, preferably tantalum pentafluoride, niobium pentafluoride and mixtures thereof. With tantalum pentafluoride not only tantalum pentafluoride itself but also other fluorides ξ »B. Ions such as Ta ₂ F,., -, Ta ₃ F. ,, - and similar which can be formed when tantalum pentafluoride is mixed with hydrogen halide . This also applies in a corresponding form to other metal halides.

The second component of the catalyst system is a hydrogen halide. Hydrogen bromide, hydrogen chloride and hydrogen fluoride, among others, are suitable, with hydrogen fluoride is preferred.

According to the invention, it has been found that the selectivity with respect to branched C ₁ -C 1 -alkylates is improved more by the use of hydrogen halide than by the use of other acids such as fluorosulfuric and trifluoromethanesulfonic acid in conjunction with a metal halide. This is mainly due to the fact that the formation of intermediates such as esters, polymerization reactions and the like are restricted to a minimum. It is believed that such undesirable reactions are kept to a minimum because, in the presence of hydrogen halide, no carboxyl

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acid esters are formed. As a result, acid dilution and consumption due to simultaneous self-alkylation, Polymerization reactions, etc., that is, reactions leading to the destruction of the catalyst, worse Product quality and excess consumption of hydrocarbon feedstock lead to being limited to a mini-space. Another reason that with the hydrogen halide according to the invention containing acidic systems a higher selectivity with respect to branched C ^ -C. "-Alkylates obtained the lower solubility of the unsaturated organic materials e.g. the olefins in the above-mentioned be oxygen-free acids.

It has also been found that the alkylation process according to the invention is more effective when carried out in the substantial absence of aromatic compounds. Aromatic compounds are easily alkylated to more basic compounds, which in turn act as the acid catalyst dilute and thus worsen its effectiveness. For this reason, aromatic compounds should be used in the starting material not be present in amounts greater than about 1% by weight.

The effectiveness of the catalyst depends directly on the molar ratio of hydrogen halide to Lewis acid. When behaving

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nism moderately small, i.e. less than equimolar amounts of hydrogen halide relative to Lewis acid, part of the Lewis acid is indeed dissolved and the reaction thus started set, but the rate of response is inappropriately slow. With equimolar amounts of hydrogen halide and Lewis acid increases the rate of the reaction. The magnification of the molar ratio of hydrogen halide to Lewis acid leads to the fact that more Lewis acid is dissolved and as a result, the liquid phase catalyst is more conducive to the reaction is formed. This effect becomes more important when the molar ratio of hydrogen fluoride to Lewis acid is greater than 1 and continues as the amount of the liquid phase catalyst increases. Hence, the molar ratio is Hydrogen halide to Lewis acid is preferably at least 2: 1 and more preferably at least 5: 1. Too large surpluses Eventually, hydrogen halides lead to a decrease in acidity of the reaction system, thereby producing the above effect will be annulled. If a carrier is not used, the catalyst can be used depending on the ratio of the catalyst components a homogeneous solution of the metal halide in hydrogen halide or a mixture of solid and dissolved metal halide be in hydrogen halide.

The concentration of the above-described catalyst in the alkylation process of the invention is not critical.

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ORIGINAL INSPEOTED

Generally the catalyst will be used in catalytic amounts. In the case of -paraffin-01efin alkylation, the Olefin concentration on the catalyst at the time of Olefin addition be kept low, that is, the amount of olefin fed per unit time must be in relation to the catalyst flowing past must be low. The one with the catalyst The amount of olefin contacted may therefore be in the range of about 0.0001 to 0.05, and preferably in the range from 0.0001 to 0.01 parts by volume of olefin per part by volume of catalyst lie in the reaction mixture.

In paraffin-paraffin alkylation, the amount of larger wax contacted with the catalyst ranging from about 0.1 to 10, and preferably from 0.25 to 5 parts by volume of larger paraffin per part by volume of catalyst lie in the reaction mixture. The volume percent texl of the catalyst in the emulsion mixture, i.e. im liquid hydrocarbon plus catalyst, lies between about 30 to 85, and preferably between about 50 and 70%.

The catalyst can be used neat, diluted or in solid form, for example adsorbed on a solid support will. The catalyst adsorbed on a support can be in fluidized beds, in a molten salt process or in suspension be used in a reaction mixture. at

using the catalyst in solution can use any solvent are used, which under the specific reaction conditions of the hydrocarbon conversion compared to the Catalyst is inert. For best results, use a solvent or diluent to remove catalyst poisons how water and the like are pretreated. Suitable diluents or solvents include Sulfuryl chloride fluoride, sulfuryl fluoride, sulfolane, fluorinated Hydrocarbons, freons, polyfluorinated polyhalogenated Hydrocarbons and mixtures thereof. When using a metal fluoride as Lewis acid in the catalyst system the preferred diluent used is hydrogen fluoride. By using a solvent or diluent the viscosity of the catalyst mixture can be regulated. The proportion of the diluent can be very high fluctuate and make up to 98% by volume of the catalyst mixture. The volume ratio is preferably from Solvent to catalyst, however, about 20: 1 to 1: 1. In the case of strongly exothermic reactions, larger dilutions can be used to be required.

The catalyst can be mixed in the absence of diluents. The catalyst components can be separated i.e. in the absence of the reactants, or in situ, i.e. in the presence of them. In general

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the order of addition of the reactants is not critical.

All support materials are suitable as solid supports for the catalyst, which are inert to the catalyst under the reaction conditions. Otherwise the carrier should be pretreated e.g. heated, chemically treated or coated to remove substantially all of the water and / or remove hydroxylic sites. Reactive carriers can be made inert by covering them with an inert material coated like antimony trifluoride or aluminum trifluoride or treated with freons, fluorine or fluorinating compounds if the catalyst contains e.g. hydrogen fluoride. Suitable solid support materials include fluoride-treated or coated resins such as sulfonated resins Cation exchange resins, fluoride-treated acidic calcites such as alumina and aluminum silicates, and acid-resistant ones Molecular sieves such as faujasite and zeolites, graphite, Chromosorb T, Fluoropak 80 etc.

The supported catalyst can be in various For example, by conventional methods such as dry blending, coprecipitation or impregnation getting produced. In one embodiment, a suitable deactivated carrier is treated with a Lewis acid such as Tantalum pentafluoride and then with a hydrogen halide

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like hydrogen fluoride impregnated. The weight ratio of Lewis acid and hydrogen halide to carrier can range from 1: 100 to 1:10.

Olefins with 2 to 8 carbon atoms and in particular with 2 to 6 carbon atoms are suitable for the process according to the invention per molecule. In addition, the reaction mixture can contain small amounts of diolefins. The olefins can be used in both gaseous and liquid form. The method according to the invention also allows its use of polymers, copolymers, interpolymers, cross polymers, etc. of the above olefins such as diisobutylene and Triisobutylene polymers, the codimer of n-butylenes, and the like. These polymers break down into smaller fragments and can then be alkylated according to the invention. Mixtures too of the above-mentioned olefins can be used.

Paraffinic hydrocarbons such as aliphatic and cycloaliphatic hydrocarbons are suitable as starting products for the process according to the invention. The suitable straight-chain and branched aliphatic hydrocarbons contain 4 to 12 (XC ₄ -C ₁₂ ) and preferably 4 to 8 carbon atoms (1C ₄ -C ₈ ) and are, for example, isobutane, pentanes, hexanes and heptanes. The suitable cycloaliphatic hydrocarbons (naphthenes) contain 5 to 15 and

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preferably 6 to 12 carbon atoms and are for example Methylcyclopentane, dimethylcyclopentane, ethylcyclohexane and n-pentylcyclohexane.

Hydrocarbons are also suitable for the process according to the invention with more than 12 carbon atoms per molecule, for example Polymers, paraffin waxes and the like are suitable as starting materials. Such starting materials, however, are not directly alkylated, as paraffinic compounds with more than about 8 carbon atoms per molecule in a strongly acidic environment are less stable and tend to break down into more stable, less carbon-containing intermediates. According to the invention, these intermediates are then alkylated to give the desired liquid products. It is believed, that cycloaliphatic hydrocarbons also react in the same way but with a slower reaction rate.

The inventive method is also for the alkylation of a Paraffins with a different paraffin are suitable. A lower paraffin like isobutane, isopentane, isohexane or theirs Mixtures containing starting material can, for example, with higher paraffins containing more than 6 carbon atoms contain, are alkylated to low molecular weight materials. For example, isobutane can be combined with heptane to form pentanes and

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Hexanes or with octane to essentially hexanes or isopentane with heptane to form hexane products.

The catalyst system of the present invention is particularly suitable for refinery alkylation processes since various refining materials can be used as starting materials. For example, C ₂ 1 Ct, C. and / or C ₁ - olefin purchases from thermal and / or catalytic cracking, butanes (field butanes) that have previously been subjected to an isomerization and partial dehydrogenation treatment, bottom residues from refining (refinery stabilizer bottoms ), usually gaseous products from sulfuric acid or phosphoric acid catalyzed polymerization and copolymerization processes and normally gaseous products from thermal and / or catalytic cracking are excellent starting materials for the process according to the invention. Such starting materials are dried to about 0.5 to 15 and preferably about 0.5 to 2 ppm by weight water content prior to addition to the reactor in order to avoid excessive water accumulation when the reaction is carried out.

In the case of paraffin-oil-fin alkylation, the molar Ratio of olefin to paraffin in the feed of 1: 1 up to 1: 200, better from 1: 3 to 1:50 and preferably from 1: 5

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up to 1:50. In general, a high dilution of the olefin is sought to avoid competing side reactions such as Prevent olefin polymerization and self-alkylation. In addition, the concentration of the olefins should therefore also be be low so that substantially all of the olefin is protonated. The method according to the invention is therefore preferred carried out at a low olefin addition rate compared to the catalyst addition. In the case of paraffin-paraffin alkylation should maintain an excess of the lower paraffin compared to the higher paraffin will. The molar ratio of lower paraffin to higher paraffin in the reaction zone is usually in Range from about 2: 1 to 100: 1 and preferably from about 3: 1 to 20: 1.

For carrying out the alkylation process according to the invention the presence of hydrogen is required. The hydrogen serves to limit possible cracking reactions and for the hydrogenation of free intermediates, polymeric materials and other unsaturated compounds that occur in the course of the reaction are formed and can thus be present in the acid phase. This effect of the hydrogen extends the Life of the catalyst system.

The concentration of hydrogen in the acid catalyst during the alkylation is not critical provided it is

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sufficient to saturate the intermediates formed when polymers break down during alkylation. Concentrations of about 0.1 to 5% by weight, based on the hydrocarbon feedstock, are sufficient, although larger amounts of hydrogen can be used. The hydrogen can be present in pure form or in the form of a hydrogen-containing gas. Hydrogen from petroleum reforming and hydrogen plants as well as exhaust gases from all hydrogenating processes or hydrogen-evolving organic compounds such as tetralin, methylcyclohexane, decalin, isobutane and the like can be used. The term hydrogenating processes means processes such as hydrofining, hydrocracking, hydrogenative desulfurization and similar processes or syntheses in which hydrogen is obtained as a reaction product. The gas containing hydrogen can also contain, inter alia, gaseous hydrocarbons (C ₁ -Cg), carbon monoxide, carbon dioxide and hydrogen sulfide. Depending on the type of starting material and the alkylation conditions, some of the light C ..- Cg hydrocarbons are alkylated to form an additional liquid product. The hydrogen-containing gas can be fed to the alkylation process directly or in admixture with the hydrocarbon feed and should preferably be dry.

The catalyst system of the invention is somewhat sensitive to impurities such as water, so that the invention

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proper alkylation procedures in the absence of major amounts Moisture and preferably under substantially anhydrous conditions, that is, based on the Lewis acid des Catalyst in the presence of less than 5 and preferably less than 2 wt.% Is carried out water.

The temperatures in the alkylation process according to the invention are generally between about -100 and +100 ⁰ C, better between about -30 and +75 C and preferably between about -10 and +60 C. The pressure required to carry out the reaction depends on the starting product, the diluent, the purity of the hydrogen, and other process variables. As the hydrogen concentration decreases, the pressure must be increased. The pressure should usually be sufficient to keep at least a portion of one of the catalyst components in the liquid phase. The alkylation process according to the invention is preferably carried out in the liquid phase when using a catalyst system containing no support. This can also be expressed in terms of the partial pressure of hydrogen, which should be at least 0.1 atmospheres and can be in the range from about 0.1 to 100 atmospheres, more preferably from about 0.1 to 50 atmospheres and preferably from about 0.3 to 25 atmospheres . The total pressure can be between about 0.1 and 150 atmospheres. The alkylation according to the invention can be carried out in the presence of an inert gas such as nitrogen

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substance, however, in the absence of an oxygen-containing gas, that is to say with an oxygen content of the inert one Atmosphere forming gas of less than 1 wt.% Performed v / earth »

The contact time of the reactances in the presence of the catalyst can be varied depending on the desired degree of alkylation. The contact time required depends in part on the temperature, the olefin used and the catalyst concentration from »Usual contact times are about 0.05 seconds to several hours, better e - '; - wa 0.05 seconds to 1 hour and preferably about 0.05 seconds to 45 minutes. The amount of catalyst to be used can vary considerably and is generally so great that the volumetric throughput of olefin is about 0.01 to 1 and preferably about 0.04 to 0.2 V / h / V (volume of olefin per hour per volume of catalyst).

The alkylation process according to the invention can be carried out batchwise, be carried out semi-continuously or continuously, a continuous procedure is preferred in order to avoid secondary reactions of the products as far as possible. In general, for alkylation processes, the yield of saturated product increases with increasingly intense contact between starting material and catalyst increases. That's why

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Conventional equipment containing one or more reactors with adequate agitation equipment can be used such as mechanical stirrers, turbo mixers, jet mixers and the like. One or also multiple reactants can be supplied via dispersing devices such as nozzles with reduced inner diameter, porous bushings and similar are entered into the reaction zone. The hydrocarbon phase containing paraffin-olefin or paraffin-paraffin, the catalyst phase and the gas containing the hydrogen can be in cocurrent, crossflow or countercurrent be passed through one or more reactors. After a sufficient time, unreacted reactants, partially deactivated catalyst, inhibitors and heavier reaction products from the alkylation products and also from each other for example, separated by distillation and completely or partially recycled into the alkylation zone will. If desired, the partially deactivated catalyst can be regenerated or reactivated by suitable treatment and returned to the alkylation process.

As with other alkylation processes, better quality control of the end products can be achieved if that Reaction system is equipped with a recycle device, wherein the partially reacted hydrocarbons mixed with fresh input product and added to the

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Dispersing devices are returned to the reaction zone. Because of the high conversion efficiency of the invention Catalyst system, however, the alkylation is preferably without recycling and with short contact times carried out.

The alkylation process of the invention provides alkylates with more branched isomers that have a higher octane number than possess the hydrocarbon feedstocks. The alkylation products obtained are particularly suitable as admixtures to refinery motor fuels.

example 1

In a 300 ml "Hastelloy C Autoclave." Engineer's "were 27.6 g of tantalum pentafluoride (0.10 mol), 2.8 g hydrogen fluoride (0.15 mol) and 52.2 g isobutane (0.19 mol) heated to 40 ° C. Then 2.8 g of ethylene (0.1 mol) under a pressure of 9.84 atmospheres and hydrogen (0.07 mol) was introduced under a pressure of 7.03 atmospheres into the reaction mixture, which was stirred at about 1600 rpm. While the addition of the very strongly exothermic ethylene, cold water was passed through an internal cooling coil to a Maintain a temperature of 40 C. Any increase in temperature would result in a loss of ethylene through polymerization cause an appearance that both by the presence of

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excess hydrogen fluoride as well as excess Hydrogen is balanced. Connected to the reactor by means of an evacuated stainless steel A sample was taken from 10 ml of the cylinder at 40 ° C. When the valves connecting the two vessels were opened, there was a flow due to the pressure difference reaction product through the dipstick into the smaller vessel. The sample was set to -70 C cooled and a measured portion of the vaporized liquid was placed in a flame ionization detector Perkin Elmer 900 gas chromatograph using a DC-200 capillary column analyzed at 50 ° C. With the exception of the reactants used, the product composition was as follows:

Product distribution%

traces

C ₃ 7.3

iC ₅ 7.3

nC ₅ 1, 8

Hexanes 83.6

2,2-DMC ₄ lanes

2,3-DMC ₄ 67.4

2-MP 23.9

3-MP 8.7

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Example 1 shows that the catalyst system according to the invention A high selectivity with regard to the formation of hexane and branched components in the hexanes with a higher octane number owns. For example, except for the reactants, the products consist of about 83.6% hexanes, with about 67% of the hexanes are 2,3-dimethylbutane.

Example 2

55.2 g of tantalum pentafluoride were placed in a 300 ml stirred autoclave (0.20 moles), 40.0 grams of hydrogen fluoride (2.0 moles), 116 grams Isobutane (2.0 moles), 40 grams of n-heptane (0.4 moles), and hydrogen (approximately 0.35 atmospheres, 0.004 moles) at a rate of agitation from 1000 rpm, stirred and heated to 40.degree. After about 30 minutes at 40 C a sample was taken and how analyzed in example 1. The following table shows the results, not taking the reactants into account are.

Product distribution

^C 5 ^C 6

iC _c in C _c

2.2 DMC ₄ in

63, 7th 29 10 7, 2 82, 7th 52, 4th

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Example 2 shows that the catalyst system according to the invention also very active and for paraffin-paraffin alkylation is of high selectivity for the formation of the desired branched, high octane isomers.

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Claims (11)

Claims ί 1. / alkylation process, characterized in that a paraffinic feedstock with a content of iso-aliphatic C.-C ₁ hydrocarbons and / or cycloaliphatic C ^ -C ₁ ^ hydrocarbons under substantially anhydrous alkylation conditions and in the presence of Hydrogen and a catalyst with one or more hydrocarbons from the group of paraffins and / or olefins in contact, the catalyst (a) bringing one or more Lewis acids of the formula MX, in which M one or more elements from group IIIA, IVB, V and / or VIB and X are halogen and η is the ratio of halogen to M varying from 1 to 8, and (b) contains a hydrogen halide so that an alkylate product having a higher octane number than the feed is formed. 2. The method according to claim 1, characterized in that one hydrogen halide and Lewis acid at least in equimolar amounts and preferably in a molar amount Ratio of at least 2: 1 used. 3. The method according to claim 1 or 2, characterized in that the Lewis acid used is tantalum pentafluoride, niobium penta- 609852/1 084 fluoride or mixtures thereof and as hydrogen halide Hydrogen fluoride used. 4. The method according to claim 1 to 3, characterized in that that a C ₀ -C ₀ olefin is used as the olefin. ^ ο 5. The method according to claim 1 to 4, characterized in that there is a feed product with a molar ratio used from olefin to paraffin from 1: 1 to 1: 200. 6. The method according to claim 1 to 3, characterized in that one is a paraffin with more than 6 carbon atoms brings into contact with the paraffinic feedstock. 7. The method according to claim 1 to 6, characterized in that sufficient hydrogen is supplied so that a Hydrogen partial pressure of at least 0.1 atmospheres is maintained. 8. The method according to claim 1 to 7, characterized in that the alkylation is essentially in the absence of aromatic compounds. 609852/1084 9. The method according to claim 1 to 8, characterized in that that the alkylation is carried out essentially in the liquid phase. 10. The method according to claim 1 to 9, characterized in that the catalyst is applied to a support is used, the carrier being essentially inert to the acid applied. 11. The method according to claim 1 to 10, characterized in that the alkylation is carried out at a temperature of about -100 ° to + 100 ° C and a hydrogen partial pressure of about 0.3 to 25 atmospheres. ue: ka: kö 609852/1084